1. Field of The Invention
This invention relates to the field of bicycles, tandem tricycles, and to bicycle accessories. Specifically, the present invention is an attachment that enables the rapid conversion of two standard two-wheeled, single rider bicycles into one double rider, three in-line wheeled, tandem tricycle.
Two problems arise when touring or simply riding in groups of two or more cyclists. First, it is difficult to speak to fellow riders while maintaining a safe distance. Second, riders often become separated due to differences in fitness, cycling capability, and equipment. Tandem bicycles, i.e., the well known two-wheeled, bicycle-built-for-two, overcome these problems for two riders. Tandems also have the advantage of increased speed as a result of reduced drag as compared to two individual bicycles. However, tandems are expensive, difficult to store, and can only accommodate two cyclists. Tandems also do not offer the individual freedom and maneuverability of a solo bicycle. It is desirable to be able to enjoy the benefits of each at a moment's notice, by being able to switch from a single rider bicycle to a double rider tandem, and vice versa, easily and economically. Two or more people could then cycle to a destination, linked together, conversing easily on the way, and arrive together, regardless of their respective pedaling speeds. Upon arrival, they would have the option of remaining in tandem or of detaching their bicycles and enjoying the advantages of solo cycling on individual bicycles.
The present invention therefore relates to an accessory which would allow two or more conventional bicycles to be quickly and easily linked together to create a tandem and which would allow the reverse to be accomplished in the same manner.
2. Description of Related Art
The desire for a tandem relationship between riders without the necessity of buying and storing a conventional tandem bicycle has been around for a long time. Inventions therefor have taken various styles and constructions. They can be roughly grouped in three classes: trailers, major reconstructions, and adapted bicycles.
In the most rudimentary tandems, the trailing vehicle is merely towed, and the trailing person is no more than a spectator, inasmuch as there is no motive power, pedals, etc., provided for the trailing vehicle. The trailers are attached by some sort of trailer hitch to either the seat posts, the seat stays, or the chain stay of the lead bicycle, or the equivalent elements on a motor scooter or motorcycle. Typical of this class are the British patent to Gyro et al, 422,768, 1-1935, the French patent to Picot, 873,105, 6-1942, the French patent to Passera et al., 1,091,332, 4-1955, and the U.S. Pat. Nos. to Manngarn (2,756,069), Mc Clellan (3,387,859), Howard (3,653,679), Vanderhorst et al. (4,274,649), and Fake (5,076,600).
A second class of tandem tricycles provides a motive means for the trailing vehicle. The trailing vehicle resembles a bicycle, but is either a major modification thereof, such as by a complete removal of the trailing bicycle's handlebars, front fork, and front wheel, or a reconstruction thereof by manufacturing a special bicycle, in reality a monocycle, since it has but one wheel. Usually they are attached to the leading bicycle's seat post or seat post housing by an elongated frame member. Representative of this class are the U.S. Pat. Nos. to Humber (305,690), Jakobson (552,907), O'Connor (5,067,738), and Adams (5,470,088), and the Swiss patent to Fritschi, 185,820, 8-1936. The U.S. Pat. No. to Du Bois (2,271,255), and the Soviet Union patent 1,756,196, 9-1992, add a structural brace between the frame of the trailing monocycle and the leading bicycle's rear axle.
Finally, there are the various tandem tricycles comprising two almost-conventional bicycles, in which the front fork of the trailing bicycle is attached to the rear axle of the leading bicycle. This class is characterized by the necessity to modify the rear axle and/or the front fork. The standard rear axle is either replaced by a longer one in order to permit mounting of the front fork thereon e.g., Hunt (598,872), Straub (658,406), Strong (4,458,908), and Teel (5,522,610)! or an extension is attached to the rear axle to accommodate the front fork e.g., Larson (5,372,371)!. Tandem tricycles which attach the trailing bicycle to the rear axle of the leading bicycle have to cope with the fact that the rear wheel axle mechanism includes the gear transmission, e.g., a derailleur, which makes the rear fork and rear wheel axle bigger and wider than the front wheel fork and axle. To compensate therefor, the front fork is replaced with a modified fork, wider than the original fork, and specially formed to fit around the leading bicycle's transmission (Strong, Larson, and Teel, supra, are examples). Both of these modifications are undesirable. Axle extensions are potentially hazardous, particularly during trail or mountain biking. Further, any modification of the front fork assembly is costly and thereafter requires a complementary modification of the front wheel used therewith.
Jakobson (579,982), and Carswell (1,300,343) retain unchanged the conventional leading bicycle's rear axle and the trailing bicycle's front fork. Instead of modifying them, they provide an adapter which is rotatably mounted for limited movement on the leading bicycle's rear axle and which is rotatably attached to the front fork of the trailing bicycle. Their solutions were acceptable for single speed bicycles but will not likely work on modern multi-speed bicycles. Also, although neither Jakobson nor Carswell mentioned it, attachment of their adapters would seem to require longer rear axles, with the concomitant disadvantage mentioned before.
There are other examples of conversions of two bicycles into a tandem, but they embody isolated concepts. For example, Busseuil (4,261,592) attaches a tow bar between the two bicycles, producing a four-wheeled tandem which each cyclist steered independently.
There remains a need, therefore, for a means whereby two standard single rider, multi-speed bicycles can be rapidly converted into a single tandem tricycle without major, costly modifications to either bicycle. The present invention satisfies that need.